Zonular ligament abnormalities intermingled in acute primary angle closure: A diagnostic and therapeutic challenge.

ABSTRACT

Purpose: This study aims to investigate patient characteristics with lens zonular ligament abnormalities in Acute Primary Angle Closure (APAC), identifying related risk factors, and evaluating the efficacy of Pilocarpine, a miotic agent. Design: Retrospective case-control study. Methods: Conducted as a retrospective case-control study at Hebei Provincial Eye Hospital from January 1, 2019, to December 31, 2021, the study included APAC cases undergoing ultrasound phacoemulsification with or without glaucoma surgery. Zonular ligament status was determined by intraoperative indicators such as lens equator visibility post-mydriasis and anterior capsule wrinkling during capsulorhexis. Patients were categorized into APAC and APAC with Lens Subluxation (APACLS) groups. Demographic details, Central Anterior Chamber Depth (ACD), Axial Length (AL), ACD difference between eyes (ACDD), Lens Thickness (LT), Lens Position (LP), and Relative Lens Position (RLP) were recorded and compared. Pilocarpine's impact on intraocular pressure reduction was assessed. Statistical analysis involved bilateral t-tests (for normally distributed data comparing both eyes in each group), non-parametric tests (for comparing two groups with non-normally distributed data), binary logistic regression, and Receiver Operating Characteristic (ROC) curve analysis for cutoff value determination related to zonular abnormalities. Results: The APAC and APACLS groups showed no significant difference in age of onset (70.11 ± 8.67 years vs. 70.11 ± 8.67 years, P = 0.159) or axial length of the eye (22.35 ± 0.64 mm vs. 22.36 ± 0.78 mm, P = 0.929). In the APACLS group, LT was greater (5.24 ± 0.37 mm vs. 5.01 ± 0.36 mm, P = 0.011), ACD was shallower (1.42 ± 0.24 mm vs. 1.69 ± 0.24 mm, P = 0.000), and ACDD was larger (0.38 ± 0.22 mm vs. 0.18 ± 0.18 mm, P = 0.000). The LP was lower (4.04 ± 0.32 vs. 4.20 ± 0.22, P = 0.013), and RLP was also lower (0.18 ± 0.02 vs. 0.19 ± 0.01, P = 0.015) in the APACLS group. A shallow ACD and a large ACDD were identified as risk factors associated with lens zonular abnormalities in the affected eyes (ACD OR value 63.97, P = 0.027; ACDD OR value 0.029, P = 0.027). Using ROC curve analysis, the cutoff value for ACDD was determined to be 0.375 mm, and for ACD, it was 1.6 mm. After pupil constriction with Pilocarpine eye drops, the proportion of patients whose intraocular pressure normalized was 75.36 % (52/69) in the APAC group and 71.43 % (25/35) in the APACLS group. Conclusion: ACD and ACDD in the affected eye are indicative of increased risk for APACLS. An ACD <1.6 mm and ACDD >0.375 mm should prompt consideration of zonular ligament abnormalities. Pilocarpine as a miotic treatment is safe and effective for such patients.